Слава, мне неприятно это говорить, но...
When playing with the top card of your library revealed, if an effect tells you to draw several cards, reveal each one before you draw it.
If the top card of your library changes during the process of casting a spell or activating an ability, the new top card won't be revealed until the process of casting the spell or activating the ability ends (all targets are chosen, all costs are paid, and so on).
401.6. Some effects tell a player to play with the top card of his or her library revealed, or say that a player may look at the top card of his or her library. If the top card of the player’s library changes while a spell is being cast, the new top card won’t be revealed and can’t be looked at until the spell becomes cast (see rule 601.2h). The same is true with relation to an ability being activated.
401.7. If an effect causes a player to play with the top card of his or her library revealed, and that particular card stops being revealed for any length of time before being revealed again, it becomes a new object.